Revert go module changes

[Zelldon]

Description

See related slack message https://camunda.slack.com/archives/C06HTSPD5AP/p1716792823991149

What did we learned:

1. GitHub redirects help to still resolve old go modules
2. old tags with old module names are still resolvable so this was no breaking change nor any impact to the customers
3. On a new release, customers have to migrate to the new module name.

When should this change go live?

• This is a bug fix, security concern, or something that needs urgent release support.
• This is already available but undocumented and should be released within a week.
• This on a specific schedule and the assignee will coordinate a release with the DevEx team. (apply hold label or convert to draft PR)
• This is part of a scheduled alpha or minor. (apply alpha or minor label)
• There is no urgency with this change and can be released at any time.

PR Checklist

• My changes are for an already released minor and are in /versioned_docs directory.
• My changes are for the next minor and are in /docs directory (aka /next/).

• My changes require an Engineering review, and I've assigned the Engineering DRI or delegate.
• My changes require a technical writer review, and I've assigned @christinaausley as a reviewer.

[akeller]

I have a follow up Q on Slack re: 8.6, but let's handle that in a separate PR so we can get these changes merged and released ASAP.